Heat transfer to supercritical fluids flowing in channels—empirical correlations (survey)

Abstract

This literature survey is devoted to the problem of heat transfer of fluids at supercritical pressures including near critical region. The objectives are to assess the work that was done in the area of heat transfer at supercritical pressures, to understand the specifics of heat transfer at these conditions, to compare different prediction methods for supercritical heat transfer in tubes and bundles, and to choose the most reliable ones. The comparisons showed there is a significant difference in heat transfer coefficient values calculated according to various correlations. Only some correlations show similar results, which are quite close to the experimental data for normal supercritical heat transfer in water and carbon dioxide. Also, no one correlation can accurately predict the magnitude and onset of deteriorated heat transfer. The exhaustive literature search, which included hundreds of papers, showed that the majority of correlations were obtained in tubes and just few of them in other flow geometries including bundles. The variations in the prediction of supercritical heat transfer are related to the significant changes in thermophysical properties near the critical and pseudocritical points. Therefore, a discussion on the general trends of various thermophysical properties at near critical and pseudocritical points is also included. Based on several chosen correlations, the heat transfer coefficients and temperature profiles in the CANDU-X reactor cooled with supercritical water were calculated.